Patent GB-1434442-A (GB)
Title: Adjustable self-propelled carriage and guide track
IPC: B23K31/02
Filed: 1974-06-19
Abstract: 1434442 Welding and cutting by fusion; grinding CRC-CROSE INTERNATIONAL Inc 19 June 1974 [27 June 1973] 27107/74 Headings B3D B3R and B3V A self-driven carriage for a tool, such as a welding, cutting, grinding or heat-treating tool, arranged for travelling along a flexible guide track attachable to, supportable on and conformable with a flat, concave or, usually, convex workpiece surface, comprises at least two sub-frames which are mutually angularly adjustable about an axis or axes, a flanged track-following guide roller mounted in each of at least two of said sub-frames, a motor driven track-engaging drive roller (usually knurled or fluted), and means for locking said sub-frames rigidly in adjusted relationship to conform the carriage with the track profile, said guiding rollers being located, in use of the carriage, on lines which extend perpendicular to the track profile and are disposed at equal distances from a similar perpendicular or perpendiculars through the or the nearest adjusting axis. As shown, the carriage comprises a rigid frame 40 supporting four sub-frames 55, 61, 60, 54 on three pins 56, 50. The centre pin 50 is permanently fixed, and the outer pins 56 are adjustably fixed, in slots 66, in the frame 40. The end sub-frames 55, 54 are further secured by bolts 71. The setting of the pins may be facilitated by scales at 91. The frame 40 is adapted to mount a welding torch, as by tapped holes 43, and support a control box 46. The end sub-frames 55, 54 mount guide rollers 27, 28 adapted to engage one edge of a flexible track 21 held in tension about a workpiece pipe, radially spaced from said pipe by feet 22, and bridged at its ends by an element 23. Preferably the guide rollers 27, 28, are double grooved to engage both the track and its bridging element. Inner sub-frames 61, 60 mount, on eccentrics 30, a further guide roller 29 and a motor driven friction drive roller 85 both of which rollers are held against the other edge of the track by adjustable springs 35 acting on the eccentrics and are individually releasable from such engagement by toggle levers 33, release of the roller 85 alone enabling manual carriage movement and release of both rollers 29, 85 enabling carriage removal. The roller 85 may be flanged or unflanged and the guide roller 29 may be replaced by an additional drive roller 85 in the ease of a heavy carriage. In Figs. 9-11 (not shown), four or five subframes are mounted on four pins the outer pins being adjustable in frame slots. The frames of the guide and drive rollers adapted to be disengaged from the track are slidable along their respective support pins, are spring urged towards a track edge, and are released by a cam device, the latter acting on one sub-frame which, after sliding movement sufficient to release its roller, acts on an adjacent sub-frame to slide the latter and release its roller. In Figs. 12-14 (not shown), two sub-frames are mounted on a single central pin, one subframe being adapted to carry the welding head and control box, and an additional roller (252) being provided adjacent a drive roller to retain the carriage on the track when the guide roller on the same side of the track is disengaged. The Specification discloses further embodiments (Figs. 15, 16, 17, not shown) including combinations of features of the above described embodiments. The drive roller may, Figs. 18, 19 (not shown), engage the cylindrical outer surface of the track and, to increase friction, a friction band, e.g. rubber, may be secured to said surface. The Specification discloses several alternative arrangements in respect of the number, form and disposition of guide and drive rollers, e.g. a flanged roller may be substituted for or used in combination with a non-flanged drive roller.